Insulating material.



Patented Nov. 26. IQOI.

0. W. JEFFERSON. INSULATING MATERIAL.

(Apgl iqation med Feb. 7, mm.

("0 Model.)

NVENTOR ATTORNEYS WITNESSES UNITED STATES PAT NT OFFICE.

CHARLES W. JEFFERSON, OF SCHENECTADY, NEW YORK, ASSIGNOR TO THE MICAINSULATOR COMPANY, A CORPORATION OF NEIV JERSEY.

INSULATING MATERIAL.

SPECIFICATION forming part of Letters Patent No. 687,531, dated November26, 1901.

' Application filed February '7, 1901; Serial No. 46,305. (No model.)

To all whom it may concern: Be it known that I, CHARLES W. J EFFER- SON,a subject of the Queen of Great Britain,

and a resident of Schenectady, in the county of Schenectady and State ofNew York, have invented certain new and useful Improvements inInsulating Material, of which the following is a specification.

My invention relates to compound insulat- :0 ing materials; and it hasfor its object the manufacture of such a material that will not only bethoroughly flexible, pliable, and nonbrittle, but that will also be ableto resist a very high electrical voltage and to withstand a very greatdegree of heat.

Electrical insulators have been made in the shape of plates or sheetsand of some comminuted or pulverized non-combustible insulating materialmixed with a hardening 2o cement. One of the disadvantages of this kindof insulator is that it is not pliable and that it is brittle and alsothat it has not the required efficiency as to insulation and durability,and the plates or sheets. so made being brittle and non-pliable are moreapt to chip and break when being manipulated or cutinto smaller piecesfor insulation. In order to remedy these defects and to give the sheetmore durability and flexibility,sheets of 0 fabric have sometimes beenintroduced into the combined insulating sheet or plate; but thedisadvantage of the use of such fabric is that it is readily carbonized,and as soon as this happens the efficiency of the insulator is 3 5impaired. Sheets of insulating material have also been made from layersof scales of mica cemented by a varnish and then the sheet so formeddried by steam and then subjected to intense pressure, so that thevarnish between the mica scales and between the layers will be expelled,leaving only sufiicient of the varnish to cause the mica scales toadhere together. The plate or sheet so formed is then subjected tointense pressure, so that the 5 different layers of mica scales areformed in to a compact sheet in a hard state. A sheet of insulationconstructed as above described makes a very good insulator; but as thesheet itself isvirtually composed of a solid mass of mica it is somewhatbrittle and not as pliable as is sometimes desired. Also with such aconstruction of insulating-sheet it is liable to crack, especially whenout into smaller pieces or trimmed. By my invention a very simple,inexpensive, pliable, non-brittle, and highly-efficient insulatingmaterial can be constructed.

My invention consists of the insulated material herein described.

In the accompanying drawings, Figure 1 illustrates in perspective asheet of insulating material showing one embodiment of my invention,said sheet being broken away at different parts to clearly show theconstruction. Fig. 2 is a fragmentary view, enlarged, in plan andshowing how the different scales of mica may be laid and are united.Fig. 3 is a fragmentary cross-section,greatly magnified, of portion ofthe insulating-sheet illustrated by Fig. 1. Fig. 4c is a similar View to76 Fig. l, but showing a slightly-modified form of insulated sheet. Fig.5 illustrates the mechanism which may be used in one stage of theprocess of making t-heinsnlating-sheet.

Similar numbers represent like parts in all the figures.

1 represents the pliable substance forming the body of my improvedinsulating-sheet and also arranged in alternate layers.

2 represents layers formed of mica scales 3, 8 said layers 2 beingunited by the substance 1 and the spaces between the scales 3 and thelayers 2 being filled in with said substance.

4 represents the flexible composition cover f or coating of theinsulated sheet.

5, Fig. 4:, represents sheets of tissue-paper or other flexible porousmaterial saturated with an insulating compound and forming part of thesheet and interposed between the outer layer and the coating orcover-4'.

6 represents a bod y-plate of a table 7, which plate may be heated orcooled by means of a pipe 8 passing under said plate.

9 is a light roller to be used in pressing down the dilferent layers ofthe sheet during the process of manufacture and for expelling gas fromthe same.

The method I prefer to use in the manufacture of my improved insulatingmaterial r Fahrenheit.

is as follows: A layer of insulating material in a fluid or semifiuidstate is first applied to a base-plate 6, said plate having previouslybeen coated with soapstone or some similar material, so that after saidlayer has become harden ed,or partly so,it may be readily scaled fromthe plate. The material which I prefer to use is an oxidized oil, andpreferably oxidized linseed-oil, as such oxidized oil forms in itself avery good insulator and is quite pliable when oxidized or dried. producethe best results, I take linseed-oil which has first been oxidized andthen dissolve it with benzin or some similar solvent. Then I prefer toadd to this dissolved oxidized oil a very small proportion of some gum,as copal-gum. This gives the oil a little more of an adhesive qualityand a little more body. After'the liquid above described is applied in alayer 1 to the base-plate 6, as above stated, a layer 2 of mica scales 3is laid on the layer 1 of said liquid, preferably overlapping eachother, thenanother layer 1 of the liquid is applied over the layer ofmica scales, and this process is continued until the sheet is of thedesired thickness, said sheet'being made of alternate layers 1 of theinsulating liquid or semiliquid and of mica scales 3. When the sheet isof the desired thickness, the plate 6 is then heated preferably, bysteam from a pipe 8. The highly-volatile quality of the benzin orothersolvcnt will have caused it to evaporate to some extent evenbeforethe plate is heated, thus turning the oil or other liquid into a gum,uniting the different mica scales and layers of the same. The heat fromthe plate wilLcause still more eva poration of the solvent and tendtodry the oxidized oil. During said evaporation and drying, while thesheet is still upon the plate, a light pressure is applied to the sheetby means of a roller 9 or other device, such pressure being sufficientto smooth and level the layers of oxidized oil and mica scales and toexpel the gas from the sheet; but such pressure must not be sufficientto squeeze out the oil or other binding compound, as such oil, which isnow transformed into a gum, is to constitute the main portion 1 of theinsulating-sheet. The sheet is then put in an oven fora short time anddried. It is then taken out of the oven and coated by dipping orotherwise in the dissolved oxidized oil or other liquid, thus fortningacoating or cover 4 to the sheet, and then hung up in the oven-say with atemperature of about 100 Fahrenheit-for about two hours, with a heatgradually increasing to about 400 The temperature of the oven is thengradually reduced for about two hours to about the degree of heat thatthe plate first became subjected to, which might be in the neighborhoodof 100 Fahrenheit. The oxidized sheet (see Fig. 1) is now complete, andit is of a very pliable character, with the oxidized and baked oil 1forming the main part or body of the sheet filling in all the spaces Inorder tobetween the mica scales 3 and between the layers of the same anduniting said scales and layers, so that the completed sheet is formed inone solid mass.

Althoughl prefer to bake the sheet,as above stated, to procure the bestresults, such sheet may be dried in any appropriate manner.

The scales of mica that I prefer to use in the manufacture of my newinsulating material are such elementary or primary scales as areunderstood in mineralogy as beingthe thinnest sheets orsingle layers ofmica that can be practically obtained by the continued process ofcleavage or splitting. The object of forming the insulating material ofsuch thin elementary scales is to prevent all liability of the differentpieces of mica splitting, which the scales might do if they werethicker, and thus cause a splitting or separation of different parts ofthe insulating material, there being no oxidized oil or other adhesi vesubstance between the separated layers of a double or multiple layeredscale of mica. Even a partial separation of difierent parts of aninsulator would leave a space for air and moisture, and thus impair theefficiency of the insulator. By reason of the use of a pliable adhesiveinsulating substance the finely-divided mica scales can be united in asolid mass with said substance, so that the resultant product is a sheetor body of very flexible and pliable insulating material that can bebent, doubled up, and twisted in any manner desired to suit the variousforms and conditions for which insulators are used. If the adhesivesubstance that binds the mica scales together were not of a flexible andpliable nature, the completed insulating product could not be bent andtwisted without liability of breaking. 7

The different layers of oxidized oil or other liquid may be applied witha brush or in any other appropriate manner, and the scales of thedifferent layers should preferably overlap those of the other layers, sothat the resistance offered to an electrical current in an insulator soformed would be transverse to the surfaces of the mica scales, therebeing always, besides the oxidized insulating compound, a scale of micato resist the force of the electrical current. Still better results maybe attained by a second coating of the plate with the dissolved oxidizedoil, and it should then preferably be hung up in the oven in a reverseposition to that in which it was suspended before. When this secondbaking is contemplated, it will not be neces sary to keep the sheet inthe oven quite aslong the first time, (or it may be otherwise dried,) asthe second baking will effect the desired result of thoroughly oxidizingand hardening the oil or body of the sheet and of uniting said body withthe mica scales in a solid mass.

The insulating-sheet made by my improved method has been found to bemost efficient as an insulator, and it will withstand a very the saidcompound, and then baking in the oven, as above described. Whenthis-form of sheet is made, very small scales of mica may be used, andit will not be necessary to use as many layers of said scales as whenthe tissue-paper or other fabric is omitted, as the layer or layers 50fflexible material will form a durable binder for the entire sheet.oxidized composition will thoroughly impregnate the tissue-paper orother fabric and render it virtually non-carbonizable. The efficiency ofsaid sheet as an insulator is equal to that in which the coating offlexible fabric is omitted.

By practical experience I find that the insulators made in accordancewith my invention will resist at least fifteen hundred volts toone-thousandth of an inch in thickness of said insulators.

What I claim as new, and desire to secure by Letters Patent, is i 1. Theimproved insulating material, consisting of layers ofa pliable,adhesive,binding substance, and layers of the thinnest or primary mica scales,the said layers united to form a solid pliable mass.

2. The improved insulating material, consisting of layers of a pliable,adhesive, insulating substance, and layers of the thinnest or primarymica scales overlapping each other, the said layers unitedto form asolid pliable mass.

3. The improved insulating material, consisting of layers of a pliable,adhesive, insulating substance, and layers of the thinnest or primarymica scales, the said layers united to form a solid pliable mass, andsaid mass having a coating of said substance.

4. The improvedinsulating material, consisting of layers of apliable,'adhesive, insulating substance, and layers of the thinnest orprimary mica scales overlapping each other, the said layers united toform a solid pliable mass, and said mass having a coating of saidsubstance.

5. The improved insulating material, consisting of layers of a pliable,adhesive, insulating substance, and layers of the thinnest or primarymica scales, the said layers united to form a solid pliable mass, saidmass being covered with a layer of thin, porous, flexible The dizedbinding substance, and layers of the thinnest or primary mica scales,the said layers united to form a solid pliable mass.

7. The improved insulating material, consisting of layers of a pliable,adhesive, oxidized insulating substance, and layers of the thinnest orprimary mica scales overlapping each other, the said layers united toform a solid pliable mass.

8. The improved insulating material, consisting of layers of oxidizedoil and of mica scales.

9. The improved insulating material, consisting of layers of oxidizedoil and of singlelayer or primary mica scales.

l0. Theimproved insulating material, consisting of layers of oxidizedoil and of singlelayer or primary mica scales, said oxidized oil forminga substantial part of the body of the insulating material and unitingsaid scales to form a solid mass.

11. The improved insulating material, consisting of layers of oxidizedoil and of irregularly-shaped mica scales.

12. The improved insulating material, consisting of layers of oxidizedoil and of overlapping mica scales.

, 13. Theimprovedinsulating material, consisting of insulating oxidizedoil, and layers of mica scales, said oxidized oil forming a substantialpart of the body of the insulating material, and uniting said scales toform a solid mass.

14. The improved insulating material, consisting of insulating oxidizedoil,- and layers of mica scales overlapping each other, said oxidizedoilforming a substantial part of the body of the'insulating material,and uniting said scales to form a solid mass.

15. The improved insulating material, consisting of oxidizedlinseed-oil, and layers of mica scales, said oxidized oil forming asubstantial part of the bod y of the insulating material, and unitingsaid scales to form a solid mass with the same.

16. The improved insulating material, consisting of oxidizedlinseed-oil, and layers of mica scales overlapping each other, saidoxidized oil forming a substantial part of the body of the insulatingmaterial, and uniting said scales to form a solid mass.

17. The improved insulating material, consisting of insulating oxidizedoil, and mica scales overlapping each other, said oxidized oil forming asubstantial part of the body of the insulating material, and unitingsaid scales to form a solid mass, and said mass having a coating of saidoxidized oil.

18. The improvedinsulating material, consisting of oxidized linseed-oil,and mica scales overlapping each other, said oxidized oil forming asubstantial part of the body of the insulating material, and unitingsaid scales to form a solid mass, and said mass having a coating of saidoxidized oil.

19. The improved insulating material, con

sisting of layers of oxidized oil and of irregularly-shaped overlappingmica scales.

20. The improved insulating material, consisting of layers of oxidizedoil and of irregularly-shaped single layer or primary mica scales.

. 21. The improvedinsulating material, consisting of layers of oxidizedcoil and of overlapping single-layer or primary mica scales.

22. The improved insulating material, consisting of layers of oxidizedoil and of irregularly-shaped overlapping single-layer or primary micascales.

23. The improved insulating material, consisting of layers of oxidizedoil and of irregularly-shaped singlelayer or primary mica scales, saidoxidized oil forming a substantial part of the body of the insulatingmaterial and uniting said scales to form a solid mass.

24:. The improved insulating material, consisting of layers of oxidizedoil and of overlapping single-layer or primary mica scales, saidoxidized oil forming a substantial part of the body of the insulatingmaterial and uniting said scales to form a solid mass.

25. Theimproved insulating material, consisting of layers of oxidizedoil and of irregularly -shaped overlapping single-layer or primary micascales, said oxidized oil forming a substantial part of the body of theinsulating material and uniting said scales to form a solid mass.

26. The improved insulating material, consisting of a pliable,dissolvable and adhesive insulatingsubstance,and layers of mica scales,said substance forming a substantial part of the body of the insulatingmaterial, and uniting said scales to form a solid mass, and said masshaving a coating of said substance.

27. The improved insulating material, consisting of a pliable,dissolvable and adhesive oxidized insulating substance,and mica scalesoverlapping each other, said substance forming a substantial part of thebody of the insulating material, and uniting said scales to form a solidmass, said mass being covered with a layer of thin porous flexiblematerial,

- and said mass andlayer having a coating of said substance.

28. The improved insulating material, consisting of a pliable,dissolvable and adhesive oxidized insulating substance,and mica scalesoverlapping each other, said substance forming a substantial part of thebody of the insulating material, and uniting said scales to form a solidmass, said mass being covered with a layer of tissue-paper, and saidmass and layer having acoating of said substance.

29. The improved insulating material, consisting of a pliable,dissolvable and adhesive oxidized insulating substance, and layers ofmica scales, said substance'forming a substantial part of the body ofthe insulating material, and uniting said scales to form a solid mass,said mass being covered with a layer of thin porous flexible material,and said mass Y and layer having a coating of said substance.

30. The improved insulating material, consisting of a pliable,dissolvable and adhesive oxidized insulating substance, and layers ofmica scales overlapping each other, said substance forming a substantialpart of the body of the insulating material, and uniting said scales andlayers to form a solid mass, said mass being covered with a layer ofthin porous flexible material, and said mass and layer having a coatingof said substance.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

CHARLES W. JEFFERSON. \Vitnesses:

ALLAN H. JACKSON, HOMER STRONG.

